0 1. Location
As the shape of the projection plane of spotlight light, spot is the yardstick to judge the light quality of lamps. High-quality facula can improve the visual texture of the object to the greatest extent, and the stereoscopic effect of the object is more prominent, and the extended light supplement is more natural.
The lens focuses the light in front of the light source in a penetrating way, and the conical surface can collect and reflect all the side light. The overlapping of these two kinds of light can get perfect light utilization, beautiful spot effect and uniform light distribution. At the same time, the reflector works synchronously, the intensity of central light gradually weakens outward, and the halo is natural and comfortable, which is undoubtedly a better spot effect.
But the light distribution of the light spot is uneven, resulting in serious black spots and dark areas. The utilization rate of the "glare" light overflowed from the spotlight cup is low, and there are many shadows at the halo boundary, stiff facula, obvious stray shadows and many virtual shadows, which will lead to visual discomfort and reduce the visibility of objects. The key point is that some light rays are directly output without being reflected by a mirror or lens. Severe glare may cause disgust, discomfort and even blindness.
02. Luminous angle
The luminous angle is also called the power angle. Usually we use half power angle, that is, the angle of 50% luminous intensity as 2&; 1/2。 The lighting angles of spotlights are generally 15, 24, 36. The light emitting angles of diodes, that is, their light scattering angles, are mainly controlled by adding a scattering agent in the diode production process. There are three types: high directivity, standard type and scattering type.
Spotlight belongs to high directivity, and is generally encapsulated by pointed epoxy or metal reflector cavity without scattering agent. Small luminous angle and high directivity. It can be used as a local lighting source, and can also be combined with a light detector to form an automatic detection system.
03. Color temperature
What is the color temperature? Simply put, it contains the unit of measurement of color components in light. Theoretically, color temperature refers to the color of an absolute blackbody heated from absolute zero (-273℃). The spectral component of the light emitted by a blackbody after heating is called the color temperature at this temperature, and the unit of measurement is "K" (Kelvin).
But the color temperature is not good or bad, only suitable or not, depending on the needs of specific places. Usually we divide lights into warm yellow light, warm white light and cold white light according to the color temperature value.
▲ Warm light is also called warm yellow light, and its color temperature is below 3,300 K, generally around 2700K K ... Warm light is similar to incandescent light, containing more red light, which can give people a warm, healthy and comfortable feeling. Suitable for families, houses, dormitories, hotels and other places, or places with relatively low temperature.
▲ Warm white light is also called neutral light, and its color temperature is between 3300K—5300K. Warm white light is soft and makes people feel happy, comfortable and serene. Suitable for shops, hospitals, offices, restaurants, waiting rooms and other places.
▲ Cold light is also called daylight color, and the color temperature is above 5300K K K. The light source is close to natural light and has a bright feeling, which makes people concentrate. Therefore, cold light is suitable for offices, conference rooms, classrooms, living rooms, libraries, exhibition windows and other places.
04. Color rendering index
Color rendering index is a parameter common to all light sources, and it is the ability to restore color. Sunlight color rendering index 100, incandescent lamp 100, energy-saving lamp 80-90, led 70-99. The lower the color rendering index, the more distorted the color is to the naked eye.
Under the condition of color adaptation with reasonable tolerance, the consistency between the psychophysical color of CIE test color sample irradiated by the measured light source and the psychophysical color of the same color sample irradiated by the reference light source is measured. The symbol is Ri. The average value of CIE 1974 special color rendering index of eight color samples is generally called color rendering index. The symbol is Ra. Saturated colors with color rendering index Ra > 90 and R9 & gt60 are selected, and the color rendering performance is excellent.